Synthesis of fluorinated trithioether compounds: X-ray structures of 1,3,5-(CH2SRf)3-2,4,6-(CH3)3C6, Rf = C6F5, 4-HC6F4, or 2-FC6H4

A series of three new trithioether compounds containing fluorinated phenyl moieties, 1,3,5-(CH2SRf)3-2,4,6-(CH3)3C6, Rf = C6F5 (1), 4-HC6F4 (2), or 2-FC6H4 (3), were prepared by treatment of 1,3,5-(CH2Br)3-2,4,6-(CH3)3C6 with the corresponding Pb(SC6F5)2 or NaSRf. The new structures were verified by elemental analyses, IR, 1H NMR, 19F NMR spectroscopies, and mass spectra. The single crystal X-ray diffraction studies of 1–3 show a similar cis,trans,trans-conformation for the three fluorophenylthiomethyl groups attached to the central benzene ring with all dihedral angles between planes of central ring and external rings close to 0°, giving flat molecules. Comparing, 1–3 with closely related tripodal molecules built-up on 2,4,6-trimethylbenzene, arrangement of one SR group respect to others seems to be defined by the nature of the R substituent. Then in the case of 1–3, a parallel arrangement of rings is favored over an orthogonal one, which would bring the ortho-F atoms close to H atoms of the methylene groups.